Robert Warren, Demographer and Former Director of Statistics for INS, Analyzes the New Pew Research Center Report on Unauthorized

New Report On Unauthorized By Pew Research Center

 On September 23, 2013, the Pew Research Center released a new report on unauthorized immigration titled, “Population Decline of Unauthorized Immigrants Stalls, May Have Reversed,” authored by Jeffrey Passel, D’Vera Cohn and Ana Gonzalez-Barrera. The next day, in a front-page article, USA Today proclaimed that, “Illegal immigration may be rising.” The article quotes various people whose comments indicate that they believe that, indeed, the number is rising again.

The Pew Research Center has consistently produced valuable and timely reports that have contributed significantly to the debate on unauthorized immigration. As in previous reports, the analysis of the data appears to have been carried out with Pew’s usual high level of statistical expertise and attention to detail. Of some concern, however, is the implication in the title of the report that the unauthorized population decline “may have reversed.” In fact, the report concludes that annual population changes for 2009 to 2011 are not statistically significant.[1] Thus, the data do not support the statements that immigration “may be” rising or that the decline in the population “may have” reversed.  Such suggestions could lead to misinterpretations of the actual results, as with the USA Today article.

Here are some key takeaways from the report [bold emphasis added]:

  • “the 2012 population estimate is the midpoint of a wide range of possible values and in a statistical sense is no different from the 2009 estimate.
  • “Different trends appear among the [top] six states… of these, only Texas had increases but no decrease in its unauthorized immigrant population over the 2007-2011 period.
  • “In 2012, 6.05 million Mexican unauthorized immigrants were in the U.S., a decline of about 900,000 from 2007.”
  • “In 2012, the number of unauthorized immigrants apprehended at the Mexican border rose modestly, to 365,000, but only because of growing apprehensions of non-Mexicans; apprehensions of Mexicans continued to decline.”
  • “There was no statistically significant annual change in 2010, 2011 or 2012, indicating that the decline has leveled off.”

As I read the report, it suggests that:

  • Unauthorized population growth has essentially been flat over the past few years.
  • The decline continues in the unauthorized population from Mexico.
  • In five of the top six states, the population was lower in 2011 than it was in 2007; the exception is Texas.
  • The improved data support previous findings of essentially zero growth in this population.

The report represents another significant contribution by the Pew Research Center on this important and timely issue. However, it does not support the conclusion that the unauthorized population is growing.

Robert Warren
Demographer and former Director of Statistics, INS


[1] As an indicator of population trends, the population estimates reported for 2012 should be disregarded because of the small sample size of the survey used to make the estimates.